In vacuum cleaning removal systems, the use of a screen to separate the dome and the shell of the receiver tank is well known as illustrated in U.S. Pat. No. 3,628,213, and our co-pending application Ser. No. 685,467. The use of air jets to clean the screen between waste removal cycles is also well known.
There still remains the problem that at various intervals, the screens must be replaced because they become clogged with oils, lint, and other debris which accumulate over time or they become damaged. In either instance, lengthy and thus costly down time results because of the known mechanisms for separating the dome from the shell. These mechanisms usually consist of a plurality of bolts and lugs arranged about the periphery of the receiving tank which must be hand actuated to both separate the dome from the shell and to then re-seal them in an air-tight manner. The extreme weight of the receiving tank, between 600 and 700 pounds, is a major contributing factor to the problems encountered when replacing the screen. Also, that the receiving tanks operate in a suspended condition is a further contributing factor.
In vacuum cleaning removal systems of the type disclosed, the use of permanent seals arranged about the periphery of the screen has not previously been done. The use of seals about the edges of screens for use in various other type systems is well known as is illustrated by U.S. Pat. No. 4,157,964. Here, U-shaped seals 68, 80 of elastomeric material are connected to a ring 72 carrying liner 42 or disk 86 which acts with edge 84 and cover 27 to seal against leakage. Here, no seal operates with both the filter and top to bring about an air-tight engagement of the tank. Also, because of the different environments, the seals of U.S. Pat. No. 4,157,964 do not confront the same pressure requirements necessary for a vacuum cleaning operation.
U.S. Pat. Nos. 4,671,873 and 4,767,427 show seals for use with filter elements, but not for use with vacuum cleaning systems. The seals disclosed are not U-shaped.
It is an object of this invention to overcome the problems as indicated in the prior art arrangements.
It is another object of the invention to provide a system for the collecting tank of vacuum cleaning systems which can act to separate the dome and shell and which can also bring them back together.
It is another object of the invention to provide means for a receiving tank of vacuum cleaning system which is capable of maintaining the dome in a position separated from the tank.
Another object of the invention is to provide means which will lock the dome against the shell under pressure sufficient to create an air-tight seal.
Another object of the invention is to provide means which will allow the dome and shell of a vacuum cleaning system to be separated and at the same time allow space to remove and replace the filter screen of the invention.
Another object of the invention is to provide a filter screen for use with a vacuum cleaning system which is equipped with a sealing member about its edges.
Another object of the invention is to provide a screen for a receiving tank with a sealing gasket which cooperates with the edges of the tank to produce an air-tight seal.